The first of the Fifth, or "Continental" Series, Silken Menace takes place in Amsterdam, with the closing paragraph being used as a link to the next story in the Series; a move reminiscent of the First Series books. At times it feels rather like a stock gangster novel uprooted and transported across the Atlantic, although the evocative canal scene and theme of Iron Curtain smuggling does render the change of location more than simply one of novelty. Rated purely on intrigue and suspense it works well although, with the exception of Hanna Janson, the characters never really come to life, leaving the various suspenseful themes to carry what otherwise might be an unremarkable gangster narrative.
The story begins with Janson touching down at Amsterdam airport, while simultaneously getting the brush-off from an attractive fellow-American traveller. No sooner has he reached his hotel room than a guest (Helga) in an adjoining room asks him to prise open the lock on her suitcase. Janson follows by inviting her to dinner, but is later visited by three men who demand - with extreme menace - an unnamed item they believe him to possess. Knocked unconscious, he is later found by Helga. The pair eat at The Cartwheel but Helga subsequently disappears while visiting the lavatory in Leidseplein Air Terminal . Janson is then separately pursued by two strangers, escaping firstly by jumping a canal cruiser and secondly by hiding out with a female night-watchman who takes pity on him (one of those strange, ostensibly unrelated interludes that crop up from time to time in Jansons).
On returning to his hotel room he receives an urgent call from Helga who implores him to meet her at an address she provides. Janson hurries there, only to discover it is a trap, and the three-man gang, led by Max Baumer Trenchart (!) beat firstly him then Helga - who is also a prisoner - in order to obtain what it is they believe him to possess. Still completely ignorant of their purpose, Janson bluffs that he has posted a document to himself at the hotel. Temporarily mollified, Max and an accomplice leave for the hotel after the surprise revelation that Helga was in fact a member of the gang and simply another ruse through which to obtain information from Janson. Helga meanwhile feels pity for Janson who, believing her to be Max's prisoner, had attempted to save her. Having firstly overpowered the third gang member, she then sets Janson free.
It transpires the gang is after a valuable Bill of Lading relating to machinery being shipped across the Iron Curtain. Janson deduces the only way they can think he possesses it is because there were two Jansons on the flight. Visiting the airport terminal his suspicions are confirmed, with his discovering the other H. Janson (Hanna) is none other than the woman who ignored him while the flight was landing. She indeed has the Bill of Lading, and a fairly complicated ruse then follows that reveals the two canal pursuers as being members of a rival syndicate to that of Max. Having paid Janson $3,000 ($500 of which he gives to Helga), Janson then sends them separately, with Helga, to the address where he had been held captive. He meanwhile hastens there with Hanna Janson, who the gang searches thoroughly before discovering the document. Helga subsequently arrives with the other two men, and a predictable fight breaks out, during which Janson escapes with his namesake, the latter clothed only in a camel-hair coat. Reaching their hotel Janson asks to search the coat and, on discovering the Bill of Lading, leaves Hanna stranded naked, and with no money, in the hotel room. Outside he destroys the document before departing on a train bound for Berlin.